Gammaherpesviruses, such as KSHV and MHV68, have developed a fine-tune equilibrium with the immune system of their host. As a result, these viruses establish a life-long persistent infection in their host without causing significant pathologies. Immunomodulatory proteins encoded by these viruses are likely to be critical regulators of this equilibrium. Our proposal focuses on K3, a protein encoded by KSHV and MHV68 that attenuates the antiviral CD8 responses. We aim to understand how this protein is regulated and whether we could circumvent its activity. We believe that this information will prove to be instrumental for the development of a KSHV vaccine.